Ned Kynaston, the much celebrated male actor of female roles – notably Desdemona in Shakespeare’s Othello - manages to wangle an invitation to dinner with King Charles II as the ‘companion’ of his male lover. Also at the dinner is Maria, Kynaston’s dresser, who has just – secretly, and illegally – played a female Desdemona in a Londonpub. Samuel Pepys, blown away by her performance, has invited her, with, perhaps, the intention of raising the matter of female actors at the dinner, knowing that the King is likely to be favourably disposed towards them. Perhaps together they can change the law banning the appearance of women playing women on the Englishstage.

Whilst at the dinner, Kynaston – full of his own talent, celebrity and arrogance – drops some subtle hints about his relationship, and is promptly abandoned by his lover at the end of the meal. Maria and Pepys also manage to raise the question of female actors, and – in the process – let drop that Maria is the actress who has lately played Desdemona. Much shock ensues, but Charles II decides that it is time for change: Maria is not condemned for her flouting of the rules, and – moreover – is patronised immediately by Pepys. She also makes a friend of Nell Gwynn. Kynaston, on the other hand, is supremely scathing of the loosening of the law.

Maria, of course, is in love with Kynaston. She watches him constantly. She has also memorised his show stopping performance of Desdemona in its entirety. The day after the dinner, she auditions for the part of Emilia in Kynaston’s Othello: her audition piece is Desdemona’s death scene, or rather, Kynaston’s Desdemona’s death scene. A woman copying a man acting a woman is much less a woman than the man, and it shows. Kynaston is scathing in the extreme. So rude, in fact, that Nell Gwynn, who had sneaked into the back of the theatre, intent on auditioning herself, marches out to talk to her beloved Charles. Nell asks Charles to change the law again, this time banning men from playing women. Charles doesn’t want to, but Nell can be very persuasive…

From this malarkey, then, ensues a situation where Kynaston is deprived of his entire career: he cannot play men – he’s not trained to, and he doesn’t want to either. They’re not beautiful enough. Maria, although now much in demand, cannot act at all (despite Pepys’s faith in her): she has also managed to render Kynaston almost unemployable. In despair, Kynaston returns to the king to ask for the law to be changed again. When he enters the palace, the king is involved in an ‘entertainment’: he is dressed as a woman (complete with moustache), and later we see Nell Gwynn dressed as a man. Charles asks him to perform a male role, Othello in Desdemona’s death scene. Kynaston’s portrayal complements Maria’s earlier one beautifully: he is as unhappy playing a man as she was playing a woman. He leaves, more despairing than when he arrived.

I’ll leave the final scenes of the play. There’s much to spoil, and I’d hate to do that. But I will say this: by the time the final scene was at its climax, I had actually dug my fingers into the foam rubber of the cinema seat. The suspense was almost unbearable, and at the same time perfectly handled. I couldn’t stand another moment of it, and wanted it to last a lot longer. It was that impressive.

To say that Crudup and Danes are good is to seriously understate the case. They are so at ease in their roles that it’s hard to take your eyes off them. Crudup primps and flounces through his female scenes, and swaggers and commands in his male ones. Danes is petite but powerful, and her expression – the glances, swoons and smiles – are just perfect (as good, say, as Kristin Scott Thomas in Four Weddings and a Funeral). The rest of the cast, though, give as good a performance: Tom Wilkinson and Hugh Bonneville are thoroughly engaging as Betterton, the likeable theatrical impresario, and Pepys, the barely despised diarist. Richard Griffiths is as fabulous as ever as the fop, Sir Charles Sedley (‘a scuff, sir, is a terrible thing’). Rupert Everett, though, is jaw dropping as Charles II: he pitches his tone perfectly, from sentimental monologue to raucous comedy. Zoe Tapper’s Nell Gwynn really does have to run to keep up with him, but run she does.

So the plot shines, and the cast beam… It’s a good film, then? Oh yes. But it’s not good just because of the plot and the cast. The idea behind the play is so intelligent. It begins as a comedy and eventually becomes a philosophical discussion about the nature of sexuality: what are the differences between a man and a woman? The philosophical climax (forgive the pun), when Kynaston and Maria share a bed, is breathtaking – who is playing the man, and who the woman? The original premise – should women be allowed to act on the stage – has been manipulated by Hatcher into a discussion of the similarities and differences between men and women. That’s one of things that makes the ending so gripping – whoever wins will sort of conclude the argument. I’d have to blow it in order to explain: you’ll get it when you see it.

It’s also a great film because of what it’s not. It’s not Shakespeare in Love. I like Shakespeare in Love, but that film’s premise is so much less than this one’s. I’m sure Stoppard wrote Shakespeare in Love in order to explain, comically, why the individual acts of Romeo and Juliet seem stylistically very different: put simply, Shakespeare was in a different frame of mind while he was writing each one – comic, energetic, romantic, fatalistic, tragic. It’s very clever, and it’s very enjoyable. But it’s hardly far reaching. I guess it’s also a ‘boy meets girl and then loses her to another boy’ sort of story (with other boy then losing her to a shipwreck), and we’ve all heard that before, too (perhaps without the shipwreck). Stage Beauty, though, asks so much more of us: what are the differences between the genders, in what ways are they important, and where do the boundaries blur?

It doesn’t take a lot of effort or engagement to watch Shakespeare in Love. It takes a great deal of engagement to watch Stage Beauty. If I was an incurable cynic, I would suggest that that was why Shakespeare in Love was a supremely successful film: and why, miserably, Stage Beauty almost vanished without trace at the cinema.